Gen VI BBC lifters

[EFI69Cam]

Does anyone now what the deal is with hyraulic rollers in the Gen 6 BBC? Crane says extended travel lifters are needed for cams over .570" lift. What I am curious about is why GM uses the stock 7.4 vortec lifter in the zz572 with a .631" lift cam?
I am building an engine on the short deck two-piece main version of the block the zz572 uses. Are the lifter bores closer to the cam in the bowtie blocks? Crane sells their version of the stock lifter for $250ish the Crane extended travel lifters are $500ish.

Any clues?
Thanks

[EFI69Cam]

Anyone?

[camcojb]

I do know the new ZL-1 block requires the taller lifters. Standard rollers won't even go down due to the taller lifter bores. Unfortunately I do not know if that is at all the case with the 572, I have never worked on that engine.

Jody

[MuscleRodz]

I do know that a lot of the Gen VI stuff will not interchange with earlier models. I ran into that problem when I rebuilt the top end on my hauler. It had locked up a roller lifter and ate a lobe.

Mike